1. Field of the Invention
This invention relates to a reflecting mirror device in a single lens reflex camera for splitting incident light from the picture-taking lens of the camera into two light beams during finder observation and for directing one light beam to a finder optical system by reflection and directing the other light beam to a metering system such as a light-receiving element by transmission.
2. Description of the Prior Art
There is known a device in which a metallic translucent film is provided on a reflecting mirror as by vaporization so that picture-taking light is split into two light beam by the translucent film. This device has suffered from a disadvantage resulting from the use of a translucent film, namely, a disadvantage that the finder image becomes colored, or the finder image becomes dark due to the absorption of light by the translucent film, or the light passed through the translucent film to the light-receiving element is decreased in quantity to reduce the metering performance. To overcome such disadvantage, there has been proposed a device in which a number of light-transmitting slits, instead of a translucent film, is provided on a reflecting mirror so that the light passed through such slits is directed to the light-receiving element while the light reflected by the reflecting surface is directed to the finder optical system. Although this device is improved in metering performance, it still suffers from a disadvantage that the width and length of each individual slit are so great that the shadows of such slit are projected on the finder image to make the finder image difficult to view as in the aforementioned conventional device.